Determine the number of "for" loops by the user

Question

f4r3in 2021-8-27

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1441799-determine-the-number-of-for-loops-by-the-user

评论： f4r3in 2021-8-30

Hi everyone

I want to write a code that takes the number of uncertain parameters from the user and creates a "for" loop according to their number and performs the calculations.

for example:

The user enters the number 4 as the number of uncertainty parameters and the code puts 4 "for" loops in a row. This way :

for i=1:I
    for j=1:J
        for k=1:K
            for r=1:R
                "calculations"
            end
        end
    end
end

Is this possible in MatLab?

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f4r3in 2021-8-27

在 MATLAB Online 中打开

Let me explain the problem further:

In the problem, the values I, J, K, R are known (for example all are equal to 7). And the calculation that is done in "for" loops is as follows: (A1 : A4 are also known)

"calculations"
Scen(:,l) = [A1(:,i);A2(:,j);A3(:,k);A4(:,r)];
l = l+1;

The only unknown issue is the number of "for" loops.

How can we implement this?

KSSV 2021-8-27

I think you can avoid using loops.....can you tell us what are those calculations?

I,J,K,R they will be always same?

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Answer 1

Chunru 2021-8-27

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1441799-determine-the-number-of-for-loops-by-the-user#answer_775449

编辑：Chunru 2021-8-27

在 MATLAB Online 中打开

% The number of iterations
ni = [3 4 2 2];         % 4 iterations [I J K R]; i is innerest loop 
idx = ones(size(ni));   % first index 
k = cumprod(ni);
for i=1:prod(ni)
    % calculate index (ignore this part if calculation independent of index)
    ii = i;
    for j=length(ni):-1:2
        ir = rem(ii-1, k(j-1)) + 1;
        idx(j) = (ii - ir) /k(j-1) + 1;
        ii = ir;
    end
    idx(1) = ii;
    disp(idx)
    
    % do calculation depending on idx
end
   1     1     1

   1     1     1

   1     1     1

   2     1     1

   2     1     1

   2     1     1

   3     1     1

   3     1     1

   3     1     1

   4     1     1

   4     1     1

   4     1     1

   1     2     1

   1     2     1

   1     2     1

   2     2     1

   2     2     1

   2     2     1

   3     2     1

   3     2     1

   3     2     1

   4     2     1

   4     2     1

   4     2     1

   1     1     2

   1     1     2

   1     1     2

   2     1     2

   2     1     2

   2     1     2

   3     1     2

   3     1     2

   3     1     2

   4     1     2

   4     1     2

   4     1     2

   1     2     2

   1     2     2

   1     2     2

   2     2     2

   2     2     2

   2     2     2

   3     2     2

   3     2     2

   3     2     2

   4     2     2

   4     2     2

   4     2     2